z3 rack swap issues

[theroundcow]

Hey everybody,

I put the desirable z3 rack in my coupe and the steering doesnt seem to return to center. The car has H&R lowering springs + Bilstein B8s. It has new upper shock mounts. I am fairly confident the infamous washer is in place but i will verify soon. I put a solid delrin steering donut in the car as well. I will be going through the front end soon and would really like to get the full experience of this steering rack, please help me determine a list of items to check to diagnose this problem. Currently, based on some forum searching, the list is :

1) Drophat/Shock mount Washer + not overtorqued
2) ensure rack spacers are installed in proper orientation (on top?)
3) Control Arms/ front Subframe components?

Thanks

[mjweimer]

Yes, generally the rack spacers are mounted on the top side of the Z3 rack. If you suspect a strut mount component, I would pop the tie-rods and spin the strut by hand to feel for any binding, etc. Should be smooth, smooth.

You mention replacing the rubber coupling in the steering with delrin...I'd check to make sure there is no binding of the U-joints, etc...maybe a longer bolt/nut interfering with the movement.


A dumb question, but did you check the level in the PS reservoir after driving for a bit? Don't know if/how you bled the rack after install but low fluid could be creating an issue, although you would hear the pump complaining if it were too low.


Good luck with your troubleshooting.

[Northern]

You mention replacing the rubber coupling in the steering with delrin...I'd check to make sure there is no binding of the U-joints, etc...

This, just because you didn't mention clearancing the steering ujoints in the OP.

[theroundcow]

Good call you guys! ill verify the ujoints clear tomorrow but i definitely did lots of dremeling and grinding to ensure smooth rotations when i did the rack swap...i will also pop the joints and spin the whole strut tower to see how it feels. the car has power steering hooked up : new belt, new reservoir, new crush seals. nothing whines when turning, i suspect its something of poor geometry upfront. i just this second want to order those solid lollipop control arm bushings from + new control arms so i can rule those components out? i also found a forum post previously where someone used different leak stop fluid or something and it brought the rack back to working as expected. The rack itself i purchased through a local bmw shop i trust very much.

[Vincenze]

You should try to install an improved steering shaft.

https://www.condorspeedshop.com/prod...ersion-kit-e30
https://www.sikky.com/product/e30-e3...haft-assembly/
https://vorshlag-store.com/products/...shaft-assembly